In order to protect military and law enforcement personnel from the hazards of projectiles, protective articles of clothing, such as vests, shirts and caps are provided. The typical ballistic resistant woven materials presently employed involve a 2-dimensional weave as shown in FIG. 1. In this type of weave, yarns are woven at right angles to one another in directions referred to as warp and weft or fill. The woven material is typically a high modulus material such as fibers of aramid, glass, quartz, polyolefins, such as polypropylene and polyethylene, and various polyesters. In addition, certain liquid crystal polymers such as polybenzothiozole and polybenzoxizole have been suggested for such purposes. Spider silk has also been considered by some sources.
The current 2-dimensional weaves are approximately 0.05 inches to about 0.08 inches thick and ballistic resistance is achieved by stacking together as many as thirty layers. The multi-layer panels are usually about 12 inches wide by 12 inches long and can range up to any thickness, depending upon the level of protection desired. For instance, a typical thickness for a class 2A protection (9 mm hand gun) is about 0.5 inches. The ballistic panels are then placed in strategic pockets in vests or jackets or similar articles of clothing to form body armor.
A disadvantage of the presently employed 2-dimensional weave configuration is that an impinging projectile tends to separate the warp and fill yarns as illustrated in FIG. 2. FIG. 2 illustrates the usual situation where the projectile separates the warp and fill yarns before being stopped at some intermediate layer. The separation caused by an impinging projectile makes it necessary to stack together several layers of the woven material in order to provide any degree of ballistic resistance. Of course, the more layers required, the heavier and less comfortable will be the particular piece of armor. Accordingly, continuing efforts are being made to provide fabrics exhibiting relatively light weight, while at the same time, exhibiting the desired degree of protection. Usually however, comfort is sacrificed for adequate performance. Balancing performance and comfort without a prohibitively expensive product is a major problem that challenges those involved in the design of soft body armor.